A Rossby Wave Bridge from the Tropical Atlantic to West Antarctica

A Rossby Wave Bridge from the Tropical Atlantic to West Antarctica A Physical Explanation of the Antarctic Paradox and the Rapid Peninsula Warming Xichen Li; David Holland; Edwin Gerber; Changhyun Yoo Acknowledgements: David Bromwich; Steve Price; Ryan Fogt Scripps Institution of Oceanography / Courant Institute of Mathematics

Background of this Study OUTLINE Recently observed climate changes around Antarctica Potential linkages of these changes to the Tropical Oceans Atmospheric Bridge between Atlantic and Austral Circulation Analysis and model study of the Atlantic-Antarctica teleconnection Physical Mechanisms and Rossby Wave Dynamics The Impacts on the Sea Ice, Surface Temperature, Land Ice Atlantic warming helps to explain Antarctic Paradox and Peninsula warming / Impacts from different tropical oceans Conclusions and Future Research Plan

I. BACKGROUND Recent Climate Change over Antarctica Surface Temperature Changes : Marie Byrd Land Vaughan et al. 2003 D. Bromwich et al. 2012

I. BACKGROUND Recent Climate Change over Antarctica Sea Ice Redistribution : Response to ABSL Vaughan et al. 2003 D. Bromwich et al. 2012 Yuan 2001, 2004 Stammerjohn. 2008

I. BACKGROUND Recent Climate Change over Antarctica Recent Climate Changes over Antarctica Rapid Regional Warming (10 times of GHG warming) Sea Ice Redistribution (Extension and Redistribution)

I. BACKGROUND Recent Climate Change over Antarctica Recent Climate Changes over Antarctica Rapid Regional Warming (10 times of GHG warming) Sea Ice Redistribution (Extension and Redistribution) Accelerated Land Ice Melting Change of Radiative Forcing can hardly explain all of these changes

I. BACKGROUND Recent Climate Change over Antarctica Atmospheric Circulation Variability: ABSL Vaughan et al. 2003 D. Bromwich et al. 2012 Yuan, Martinson 2001, 2004 Stammerjohn. 2008 Thompson et al. 2002, 2011 Fogt et al 2012

I. BACKGROUND Tropical Polar Teleconnections Teleconnections : Tropical Anomaly Generates Rossby Wave Karoly, Hoskins 1981, 1989

I. BACKGROUND Tropical Polar Teleconnections Teleconnections : ENSO Interacts with SAM and PSA Karoly, Hoskins Bromwich 1981, 1989 2002 Fogt 2006

I. BACKGROUND Tropical Polar Teleconnections Teleconnections : Potential Effect from Central Pacific Warming Karoly, Hoskins Bromwich Ding et al. 1981, 1989 2002 2011, 2012 Fogt 2006

I. BACKGROUND Tropical Polar Teleconnections The Focus of the Research Question Previous Studies Focused on The Pacific Antarctic Teleconnection Largely due to ENSO dominating the Interannual Variability On Decadal time scale, the Atlantic Multi-decadal Oscillation is a Leading Mode of Global SST Variability

I. BACKGROUND Tropic of this Study The Focus of the Research Question Previous Studies Focused on The Pacific Antarctic Teleconnection Largely due to ENSO dominating the Interannual Variability On Decadal time scale, the Atlantic Multi-decadal Oscillation is a Leading Mode of Global SST Variability A Question Arises Naturally : The Role of Atlantic Ocean In the Tropical Antarctic Teleconnection.

Background of this Study OUTLINE Recently observed climate changes around Antarctica Potential linkages of these changes to the Tropical Oceans Atmospheric Bridge between Atlantic and Austral Circulation Analysis and model study of the Atlantic-Antarctica teleconnection Physical Mechanisms and Rossby Wave Dynamics The Impacts on the Sea Ice and the Surface Temperature Atlantic warming helps to explain Antarctic Paradox and Peninsula warming / Impacts from different tropical oceans Conclusions and Future Research Plan

II. ATMOSPHERIC TELECONNECTION Surface Warming over North / Tropical Atlantic Atlantic Multidecadal Oscillation (AMO)

II. ATMOSPHERIC TELECONNECTION Teleconnection, Mechanisms, and Dynamics Overview of Part II

II. ATMOSPHERIC TELECONNECTION Teleconnection, Mechanisms, and Dynamics Overview of Part II Relationship Regression Maximized Covariance Analysis (MCA)

II. ATMOSPHERIC TELECONNECTION Teleconnection, Mechanisms, and Dynamics Overview of Part II Relationship Causality Regression Maximized Covariance Analysis (MCA) Comprehensive Atmospheric Model (CAM) Mechanism Idealized Model (GFDL dynamical core)

II. ATMOSPHERIC TELECONNECTION Data Analysis : Regression Regression Analysis Against Atlantic SST Austral Winter (June July August)

II. ATMOSPHERIC TELECONNECTION Data Analysis : Regression Regression Analysis ~10,000m GPH Against Atlantic SST ~5,000m GPH Surface SLP Austral Winter (June July August)

II. ATMOSPHERIC TELECONNECTION Data Analysis : Regression Regression Analysis : Verification using ERA-interim data ~10,000m GPH ~5,000m GPH Surface SLP

II. ATMOSPHERIC TELECONNECTION Data Analyses.VS. Simulations CAM4 Simulation & Regression for All Seasons JJA SON DJF MAM

II. ATMOSPHERIC TELECONNECTION Data Analyses.VS. Simulations CAM4 Simulation & Regression for All Seasons

II. ATMOSPHERIC TELECONNECTION Idealized Simulation : GFDL GFDL Dry-Dynamical-Core : An Idealized Model Numerical Solver of the Primitive Equation Isolated from any parameterization processes Spectral dynamical core With a horizontal resolution of ~3 degree Driven by Climatological Background State From the ERA-interim Reanalysis Initial Condition Simulation The model is Neutralized with an external forcing An external perturbation is introduced in the Initial condition Model response is considered as the Evolution of the impact of this initial perturbation

II. ATMOSPHERIC TELECONNECTION Idealized Simulation : GFDL Rossby wave trains simulated by GFDL dynamical core : JJA GFDL initial condition simulations show clear Rossby Wave Trains Transport to Amundsen Sea within two weeks

II. ATMOSPHERIC TELECONNECTION Idealized Simulation : GFDL Rossby wave trains simulated by GFDL dynamical core : Seasonality JJA DJF

II. ATMOSPHERIC TELECONNECTION Data Analyses.VS. Simulations CAM4 Simulation & Regression for All Seasons

II. ATMOSPHERIC TELECONNECTION Theoretical Models & Rossby Wave Dynamics Theoretical Stationary Rossby Wave Model Dispersion relation of Rossby wave For stationary wave, is 0. Where Uk *k K 2 K 2 l 2 k 2 * U * U yy We can derive the group velocity at each location c gx 2 * k 2 K 4 c gy 2 *kl K 4 c gy c gx l k

II. ATMOSPHERIC TELECONNECTION Theoretical Models & Rossby Wave Dynamics Reflection and Blocking of Rossby Wave Trains When is too small or becomes small, U yy is too large, * U yy K * U ~ k c gy c gx l k ~ 0 Rossby Wave will be reflected When U is negative, K * becomes U imaginary Stationary Rossby Wave can no longer propagate and is blocked by the trade wind

II. ATMOSPHERIC TELECONNECTION Theoretical Models & Rossby Wave Dynamics Stationary Wave in Hoskins Karoly Model Rossby Wave is reflected several times and propagates along the southern edge of the Sub-tropical Jet

II. ATMOSPHERIC TELECONNECTION Theoretical Models & Rossby Wave Dynamics Seasonality of the Stationary Wave Trains

II. ATMOSPHERIC TELECONNECTION Summary Atlantic Antarctic Teleconnection Atlantic Antarctic Teleconnection : Tropical Atlantic Warming Dramatically Enhances the SAM and Deepens the Amundsen Sea Low

II. ATMOSPHERIC TELECONNECTION Summary Atlantic Antarctic Teleconnection Atlantic Antarctic Teleconnection : Tropical Atlantic Warming Dramatically Enhances the SAM and Deepens the Amundsen Sea Low Seasonality of the Teleconnection : Pronounced in All Seasons Except Austral Summer (DJF) Mechanisms : Stationary Rossby Wave Trains

Background of this Study OUTLINE Recently observed climate changes around Antarctica Potential linkages of these changes to the Tropical Oceans Atmospheric Bridge between Atlantic and Austral Circulation Analysis and model study of the Atlantic-Antarctica teleconnection Physical Mechanisms and Rossby Wave Dynamics The Impacts on the Sea Ice and the Surface Temperature Atlantic warming helps to explain Antarctic Paradox and Peninsula warming / Linearity from different tropical oceans Conclusions and Future Research Plan

III. SEA ICE and AIR TEMPERATURE SAT Change Air Temperature Response to Tropical Atlantic Warming Linear Observed Numerical Regression Trend Simulation

III. SEA ICE and AIR TEMPERATURE SIC Change Sea Ice Response to Tropical Atlantic Warming Linear Observed Numerical Regression Trend Simulation

III. SEA ICE and AIR TEMPERATURE SIC Change Sea Ice Response to Tropical Atlantic Warming? Linear Observed Numerical Regression Trend Simulation

III. SEA ICE and AIR TEMPERATURE Mechanism Mechanism Regression and simulation well reproduce the trend of SIC and SAT

III. SEA ICE and AIR TEMPERATURE Mechanism Mechanism Regression and simulation well reproduce the trend of SIC and SAT Mechanism : Mechanical Forcing & Thermal Advection

III. SEA ICE and AIR TEMPERATURE Mechanism Mechanism Regression and simulation well reproduce the trend of SIC and SAT Mechanism : Mechanical Forcing & Thermal Advection Marie Byrd Land warming is not well explained by this mechanism

III. SEA ICE and AIR TEMPERATURE Mechanism Potential Impact on Land Ice

III. SEA ICE and AIR TEMPERATURE Mechanism Potential Impact on Land Ice Zwally et.al 2002

III. SEA ICE and AIR TEMPERATURE Mechanism Potential Impact on Land Ice Zwally et.al 2002 Bromirski et al 2010

III. SEA ICE and AIR TEMPERATURE Summary Summary : Atlantic Impacts on Antarctic Climate Atlantic Antarctic Teleconnection Helps to Explain: The Antarctic Ice Paradox The Sea Ice Redistribution The Rapid Peninsula Warming

Background of this Study OUTLINE Recently observed climate changes around Antarctica Potential linkages of these changes to the Tropical Oceans Atmospheric Bridge between Atlantic and Austral Circulation Analysis and model study of the Atlantic-Antarctica teleconnection Physical Mechanisms and Rossby Wave Dynamics The Impacts on the Sea Ice and the Surface Temperature Atlantic warming helps to explain Antarctic Paradox and Peninsula warming Conclusions and Future Research Plan

IV. CONCLUSION Recent Climate Changes over Antarctica Atlantic Antarctic Teleconnection : SAM and ABSL Impact on The Sea Ice and Surface Temperature Rossby Wave Depends on the Background Flow : Seasonality Linearity of Tropical Impacts on the Antarctic Circulatoin

IV. CONCLUSION Discussion and Future Research Plan Ocean Ice Air Interaction is not involved in Present Study, which require more observation and coupled model simulation Observations and estimations over Antarctica is inadequate/inaccurate, and could be Better Organized

Thanks

III. LINEARITY OF DIFFERENT OCEANS Linearity & Additive Property SST Trend Separate the Ocean Basins based on Observed SST Trend Xichen Li, CIMS - NYU

III. LINEARITY OF DIFFERENT OCEANS Linearity & Additive Property SST Trend as Model Forcing Xichen Li, CIMS - NYU

III. LINEARITY OF DIFFERENT OCEANS Linearity & Additive Property Linearity & Additive Property Xichen Li, CIMS - NYU

COMPLEMENT Rossby Wave Source Xichen Li, CIMS - NYU

COMPLEMENT Spatial Pattern Strongly Project on Southern Annular Mode (SAM) with spatial pattern correlation > 0.8 Xichen Li, CIMS - NYU

COMPLEMENT Stationary Wave in Hoskins Karoly model Xichen Li, CIMS - NYU

COMPLEMENT Rossby Wave Trains Xichen Li, CIMS - NYU

I. BACKGROUND Recent Climate Change over Antarctica ABSL trend Xichen Li, CIMS - NYU